iphone 4s videos won't play in Quicktime
Hello. I've recently downloaded the lastest iphone 4s software (this may have nothing to do with the problem I have) and I've discovered that whilst the videos I've taken with the iphone camera video play on the phone itself, they won't play in Quicktime (or Real) when I've synced the phone ot the computer. The audio plays but the screen is black. I've taken 6 videos and all are the same. I've played an earlier video taken some months ago and that does play both sound and pictures. Funny thing is, when i upload the movie file (the one that plays only sound with ablack screen) from my computer to You Tube, the picture magically reappears again!
Any help would be much appreciated. Thank you.
iPhone 4S, Windows Vista